Simulations of droplet combustion under gas turbine conditions

Giusti, Andrea; Sidey, Jennifer A.; Borghesi, Giulio; Mastorakos, Epaminondas

doi:10.1016/j.combustflame.2017.01.026

Cited by 16 publications

(12 citation statements)

References 63 publications

(30 reference statements)

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“…The fundamental case of an isolated droplet in the absence of any convective motion other than Stefan flow has been considered. This canonical case has received a lot of interest in the literature [14,15,16] and is further investigated here in the context of forced ignition of kerosene droplet at high-altitude relight conditions. An ambient pressure equal to 0.3 bar was considered here as representative of high-altitude conditions with the lowest ambient temperature equal to 250 K. Chemical reactions were modelled using a detailed kinetic mechanism developed for kerosene by Dagaut and Cathonnet [17,18] with 209 species and 1673 reversible reactions, and reaction rates recommended for 1 atm.…”

Section: Methodsmentioning

confidence: 99%

“…The single droplet ignition behaviour was investigated using the code described and validated in Refs. [16,15,19], in which the unsteady transport equations of mass, energy and species in spherical coordinates are simultaneously solved for both the gaseous and liquid phases according to the algorithm described by Cho et al [20]. Details regarding the implementation of the multi-component solver can be found in Ref.…”

Section: Methodsmentioning

confidence: 99%

“…Details regarding the implementation of the multi-component solver can be found in Ref. [16], whereas the interested reader is referred to Refs [15,19] for more details on the code and the solution algorithm. Additional information about the equations can also be found in Ref.…”

Section: Methodsmentioning

confidence: 99%

“…In the presentation of the results, the mixture fraction will be used quite often to show the mixing behaviour in the droplet near field. Here, Bilger's definition of mixture fraction was used [16,15]. The stoichiometric mixture fraction for the surrogate used here is ξ st ≈ 0.063.…”

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Numerical investigation of kerosene single droplet ignition at high-altitude relight conditions

Giusti

Sitte

Borghesi

et al. 2018

Fuel

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In this study, the fundamental problem of the ignition of a kerosene single droplet in a quiescent medium at engine high-altitude relight conditions is investigated using numerical simulations. The main objective is to improve the understanding of ignition phenomena with a focus on the effect of droplet evaporation in determining the growth of the ignition kernel and flame establishment. Results show that when the droplet is fully immersed in a high

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Numerical investigation of kerosene single droplet ignition at high-altitude relight conditions

Giusti

Sitte

Borghesi

et al. 2018

Fuel

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“…Furthermore, the presence of liquid sprays, as in typical gas turbines for aeronautical application, further increases the range of scales and physical processes involved in the combustion process [34] generally making the prediction of the flame behavior more challenging. Evaporation directly interacts with the local flame structure [86,87] and a reliable numerical method should take into account such interactions.…”

Section: Turbulent Combustion Modelsmentioning

confidence: 99%

Turbulent Combustion Modelling and Experiments: Recent Trends and Developments

Giusti

Mastorakos

2019

Flow Turbulence Combust

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The development of better laser-based experimental methods and the fast rise in computer power has created an unprecedented shift in turbulent combustion research. The range of species and quantities measured and the advent of kHz-level planar diagnostics are now providing great insights in important phenomena and applications such as local and global extinction, pollutants, and spray combustion that were hitherto unavailable. In simulations, the shift to LES allows better representation of the turbulent flow in complex geometries, but despite the fact that the grid size is smaller than in RANS, the push towards realistic conditions and the need to include more detailed chemistry that includes very fast species and thin reaction zones emphasize the necessity of a sub-grid turbulent combustion model. The paper discusses examples from current research with experiments and modelling that focus on flame transients (self-excited oscillations, local extinction), sprays, soot emissions, and on practical applications. These demonstrate how current models are being validated by experimental data and the concerted efforts the community is taking to promote the modelling tools to industry. In addition, the various coordinated International Workshops on non-premixed, premixed, and spray flames, and on soot are discussed and some of their target flames are explored. These comprise flames that are relatively simple to describe from a fluid mechanics perspective but contain difficult-to-model combustion problems such as extinction, pollutants and multi-mode reaction zones. Recently, swirl spray flames, which are more representative of industrial devices, have been added to the target flames. Typically, good agreement is found with LES and some combustion models such as the progress variable-mixture fraction flamelet model, the Conditional Moment Closure, and the Transported PDF method, but predicting soot emissions and the condition of complete extinction in complex geometries is still elusive.

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Large Eddy Simulation of a Reacting Kerosene Spray in Hot Vitiated Cross-Flow

Fredrich

Miniero

Pandey

et al. 2022

Flow Turbulence Combust

Self Cite

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The evaporation and combustion characteristics of a kerosene spray injected perpendicularly into a cross-flow of high-temperature vitiated air is investigated. This fundamental flow configuration has wider implications for the future development of ultra-low emission aeronautical combustors, particularly with respect to technologies involving MILD combustion. Large eddy simulations with a Eulerian–Lagrangian framework are performed to investigate the spray evolution and the characteristics of the reaction zone for a range of conditions. For the closure of turbulence-chemistry interactions at the sub-grid scales, a transported probability density function approach solved by the Eulerian stochastic fields method is applied. A configuration based on the use of airblast atomisation is assessed first and compared with experimental observations. The effect of the atomiser air-to-liquid mass flow ratio is studied in greater detail, both in terms of the resulting gas-phase properties and the droplet evaporation process. Then, the effect of ambient pressure on the global spray flame behaviour is examined. For this part of the study, no atomising air is included in the simulation to separate the effects of ambient pressure on the spray from the interaction with the air jet. Analysis of the flame and spray properties at cross-flow operating pressures of 1 atm, 2 bar and 4 bar highlights the strong coupling between the reacting flow and droplet evaporation characteristics, which are highly affected by the penetration of the spray into a flow field characterised by relatively large gradients of temperature. The results reported in this work provide fundamental understanding for the development of novel low-emission combustion technologies and demonstrate the feasibility of applying large eddy simulation with detailed chemistry for the investigation of reacting aviation fuel sprays in hot vitiated cross-flow.

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Simulations of droplet combustion under gas turbine conditions

Cited by 16 publications

References 63 publications

Numerical investigation of kerosene single droplet ignition at high-altitude relight conditions

Numerical investigation of kerosene single droplet ignition at high-altitude relight conditions

Turbulent Combustion Modelling and Experiments: Recent Trends and Developments

Large Eddy Simulation of a Reacting Kerosene Spray in Hot Vitiated Cross-Flow

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